Key lock shift mechanism

ABSTRACT

A key lock mechanism for a keyboard wherein a shift key lever and a key lock lever are mutually coupled by bridging members spanning intermediate key levers to latch and unlatch the shift key lever for deriving a compact, shallow keyboard.

United States Patent [56] References Cited UNITED STATES PATENTS 3/1919Trone...........................

[ 72] Inventor John F. Herrmann Pittst'ord, N.Y. [21 Appl. No. 679,753

197/9sux 197/98 1,423,443 7/ 1 922 Loomis. 2,168,441 8/1939 Doty........2,226,931 12/1940 Helmond. 2,229,400 1/1941 Vickery... 2,737,281 3/1956Leonard 2,797,790 7/ 1 957 B1odgett.. 3,194,493 7/1965 Brewer....3,327,828 6/1967 Primary Examiner-Emest T. Wright, Jr.

[22] Filed Nov. 1,1967 [45] Patented Jan. 12, 1971 [7 3 Assignee TheSinger Company a corporation of New Jersey [54] KEY LOCK Sm" MECHANSMAttorneys-George W. Killian, Patrick J. Schlesinger, Charles R.Lepchinsky and Jay M. Cantor 6 Claims, 3 Drawing Figs.

ABSTRACT: A key lock mechanism for a keyboard wherein a utually coupledby B4lj 5/22 shift key lever and a key lock lever are m [50] 197/7l,72,bridging members spanning intermediate key levers to latch and unlatchthe shift key lever for deriving a compact, shallow keyboard.

PAT E NTED JAN 1 2191i INVENTOR.

JOHN F. HERRMANN BY ATTORNEY 1 KEY LOCK SHIFT MECHANISM The presentinvention relates to a keyboard mechanism and, more particularly, to akey lock mechanism for a key board mechanism.

Although the present invention is suited for more general applications,it is particularly adapted for use in a key lock shift mechanism for atypewriter keyboard. Shift and unshift functions in an electric keyboardare well known to those skilledin the art. In the past, complexelectronic shift and shift lock devices have been used to lock the shiftkey when in a downor shifted position. Other attempts have used mechani-"cal means which includea lock mechanism mounted directly on the shiftkey lever. Although the prior art mechanisms have operatedsatisfactorily for the purpose intended, they have the disadvantage ofbeing complex and costly.

7 Accordingly, it is anobject of the-present inventionto provide a newand improved key lock shift'mechanism which avoids one or more of thedisadvantages and limitations of prior art mechanisms.

It is a further object of the invention to provide a novel key lockshift mechanism of compact and relatively simple construction and whichexhibits smooth yet firm key manipulation together with quiet operation.

It is yet a further object of the invention to provide an improvedkeyboard mechanism possessing high versatility for numerous and diverseapplications, combined with consistent dependability over prolongedperiods of operation.

wherein said first shift key lever, when actuated, generates a codeindicative of the fact that succeeding codes are to beinterpreted asrepresenting upper caseletters and characters;

and wherein said second shift key lever, when actuated, generates a codeindicative-of the fact that codes generated subsequent thereto are to beinterpreted'ascodes representing lowercase letters and'characters. Thenamed first shift key lever 'may appropriately be designated a shift keylever and the second shift key lever may appropriately be designated theunshift'key lever. The shift key lever and the unshift'key lever arecoupled by a rocker arm lever'which is pivotal at a midt'point ora'tsomepoint along its length. The rocker arm lever coacts with the-shiftand unshift'key lever-to maintain an out "ofphase relationship so thatthe operation of one of thekey levers produces one of the codes'andthe-return-of that key lever-effects the operation 'of the other keylever through the rocker arm-to produce the other code.ln accordancewith the irivention, the "key-lock shift mechanism includes a key lockleverwhich is disposed parallel to the shiftand' unshift'key 'levers inspaced relationship so that-other keylevers may be interposedtherebetween and said key lock lever rests against a stop bar when thekey levers are in the normally up position.

, Also included is a pawl rotatably mounted on the key lockleverandnormally urged in a clockwise direction towards'the stop bar'bya biasing spring. The pawl includes an arm positinned-in cooperativerelationshipwith the'key lock lever-for urging-the key lock leverdownwards when the pawl is rotated counterclockwise. The key lock leverincludes a first tab bridging other key levers disposed between theshift key lever and the key lock lever. The first tab is coupled to theshift key lever so that the shift key mechanism is urged in a downwardposition whenever the shiftlockkey lever is urged in the same direction.The shift key lever includes a second *bridging memberwhich coacts withthe pawl to' rotate it-in a'counterclockwise direction wheneverit isdepressed in a downward position' to keep the pawl from engaging thestop barand converselywhenthe key lock lever is depressed within itslimitof travel, the pawl is decoupledfrom theshift-keylever and rotatedagainst the stop bar to retain the key lock lever and the keyshiftleverin the down or shifted position.

Other and further objects and advantages of the invention will appear asthe detailed description thereof proceeds in the light of the drawingforming a part of this application and'in which:

FIG. 1 is a schematic view of one embodiment of the key lock shiftmechanism embodying the present invention with some parts removed andothers broken away to better illustrate the invention; 7

FIGS. 2 and 3 are fragmentary perspective views of the key lock shiftmechanism in latched and unlatched positions, respectively.

The present invention may beembodied in a variety of different'typewriter keyboards and, is shownbyway of example in FIGS. l--3, in oneembodiment of the structure shown in US. Letters Pat. No. 3,327,828entitled "Keyboard Mechanism Having Latch'Meansf issued June 27,1967, toHugh St. Lawrence Dannatt and assigned to the same assignee asthe'present application. Only the structure necessary to show theinvention is illustrated in FIGS. l'3. For a more complete descriptionof the keyboard mechanism, reference may be made to the above-mentionedpatent whichis he'reby incorporated by reference.

Referring now more particularly to FIGS. 1-3 of the drawing, a key lockshift mechanism-embodying the present invention is shown in a keyboardstructure comprising a base plate 12, spacer bar 15, upper case or shiftkey levers l8 and 18b and a lower case or unshift key-lever 18a. The'keylevers l8 and Home positioned in spaced relation andare supported forpivotal-motion on rod 21 and haveintegrally'formed and laterallyextending rear arms 19 and 19a, respectively, which are received inindividual co'rnbslots 20 and 20a of the spacer bar 15. The key levers18,18a, and 181; are aligned with comb teeth 22 of the'spacer bar 15.The 'shiftkey lever 18 and the unshift key lever have similar featuresand structures which for the convenience-of the reader will be similarlynumbered except that a small letter a will be added to each elementassociated with the unshift key 180. In the following description, theoperation of the shift lever 18 will be described. However, it followsthat the operation .of the unshift key lever 18a is alsodescribed bysubstituting the phrase unshift key lever 18a for the phrase shiftkeylever 18" and adding an aafter the numerical designation for theappropriate elements. Exceptions to this general rule will either beobvious or noted-herein. Thekey levers 18,180,181 18c are biasedupwardly against a-common transverse stop'bar 23, by a comb spring 24.To minimize congestionin the vdrawing, spring 24 is shown under'keylever l8c onlyrltshouldbe understood that similar biasing springs24 areprovidedQunder each of the similar key leverssuchas18,1180, etc.The-unshift a plurality of key levers (not shown) which are retained ina spaced parallel arrangement. I

Elongated pawl .39 has a central longitudinal ,slot wand zissupportedfor angular and'longitudinalmovementongtheesigde of key lever"18 by enlarged hear vheadstud 41 ext eriding through the sIot40uEac'hpawl .39 isprovidedwith projection 42 which anchors-one end of biasspring; other end of which is received in aperture of projectio provided'on the adjacent and associated key lever 11 The spring 43 biases thepawl 39 in aclockwise direction normally to engage, inthe-rest positionof its associated'key lever :18, the'fo'rward end of the pawl 39 withthe stop bar-23. fl'he rear end of each pawl'39 is bent over laterallyto provide-anactuating'projection '45 whichextends through an aperture460i the key lever '18 and into engageable' relation with theforwardgend of a slide member47 associated with key leverl8 andsupportedfor pivotal and longitudinal movement in -a manner now to be considered.

As just indicated, there is associated with key lever 18 a slide member47. The slide member 47 is positioned in sideby-side relation with itsassociated key lever 18 but is maintained in slight spaced relation tothe associated key lever 18 by a small dimple 48 pressed laterally fromthe slide member 47 and also by a short longitudinal extending plateau49 likewise pressed laterally from the slide member 47. The dimple 48and plateau 49 minimizes the frictional engagement between the slidemember 47 and its associated key lever 18. The slide member 47 ispivotally supported on the rod 21 which is received in elongated slot 51of each slide member 47 to permit a limited amount of longitudinalmovement of the slide member 47. While the rod 21 could support andguide the rear end of each slide member 47 in its longitudinal movement,the sides of the slide member slot 51 would in such case preferably needto be polished to minimize the frictional forces involved. In practice,it is preferred to form slot 51 slightly wider than the diameter of therod 21. The slide member 47 is provided at its rear end with overturnedear 38 which is engaged by the slightly overturned end of an individualtooth of a comb spring plate 57, secured to a sloping rear edge of thespacer bar as shown, to provide a bias force urging movement of theslide member 47 in a rearward direction and urging movement. of the rearend if the slide member 47 in a downward direction. The slide member 47is normally latched against such rearward movement, however, by slidemember latch portion 58, which engages latch roller 59 individual to theslide member 47. The latch roller 59 is rotatably journaled on a wire60.

Upon finger depression of the shift key button 30 pivotally to depressthe associated key lever 18, the pawl actuating projection 45 of thepawl 39 associated with the depressed key lever 18 engages the forwardend of the associated slide member 47 and pivots it about the pin 52while moving it slightly forward to disengage the slide member latchportion 58 from its associated latch roller 59. Upon latchingdisengagement of the latch portion 58 and latch roller 59, an interlockportion 62 of the slide member 47 begins to be inserted between balls 63of an interlock structure formed by the balls 63 in a manner well knownto those skilled in the art and which forms no part of the invention.

As will be evident from the drawing, the latch portion 58 of the slidemember 47 has a sharply pointed nose configuration for engagement withits associated latch roller 59. So long as the apex or nose of the latchportion 58 is above the axis of the roller support wire 60, the springbias force exerted by the comb spring plate 57 on the slide member 47tends to move the latch portion 58 on its associated latch roller 59upward into fully latched position of the slide member 47. Thus, iffinger pressure on the shift key button 30 in pivoting the slide member47 in the manner just explained should be released at any time prior tothe time when the slide member latch portion 58 is positioned with itsnose an incremental distance above the axis of the roller wire 60,the'slide member 47 will restore to fully latched position. As soon asthe slide member 47 has been pivoted by finger button pressuresufficiently far that the nose of the latch portion 58 is an incrementaldistance below the axis of the roller wire 60, the bias force exerted bythe comb spring plate 57 on the slide member 47 will cause the nose ofthe latch portion 58 to ride down on the now rotating latch roller 59.The slide member 47 will now begin to move longitudinally to the rear,with the latch portion 58 continuing in engagement with the now rotatinglatch roller 59. While this is occurring, the interlock portion 62 ofthe slide member 47 moves down between and rearwardly through theinterlock balls 63 and the rearward longitudinal movement of the slidemember 47 continues until halted by engagement of the rod 21 with theforward edge of the slide member slot 51.

The lower edge of the slide member 47 is provided with coding teeth 69for generating coded signals in a manner described in the aforesaid HughSt. Lawrence Dannatt US. Pat. No. 3,327,828. By providing one or morecoding teeth 69 at preselected ones of the tooth positions on the slidemember 47 and by omitting coding teeth from all other tooth positionsthereon, the slide member 47 can, by its longitudinal movement, generatea unique code indicative of the desired shifting action and which willidentify the upper case or lower case character of subsequentlygenerated codes. The slide member 47 was unlatched for the describedmovement by manual manipulation of the shift key button 30.

One coding tooth 69 at a preselected tooth position is provided on allof the slide members including slide members 47 and 470 so that onecommon code element is generated in response to the unlatchedlongitudinal motion of any of the slide members such as 47 and 47a. Thiscommon code element is so controlled that it is generated later andterminated earlier than any of the other code elements generated by theremaining coding teeth 69 of any of the other slide members similar to47 and 47a of the keyboard. The common code element also initiates acycle of operation of the associated equipment which utilizes each codedelement generated by typical slide members such as 47 and 47a. Theassociated equipment, after progressing through a portion of its cycleof operation, supplies return electrical energization to the keyboard toeffect latch restore movement of a latch restore bail 7 The latchrestore bail is comprised by a rod 743% 75 and drive member 76. Inparticular, the latch restore bail E is movably pivoted between arearmost position shown i n full lines and a forward position. This isaccomplished by mechanical connection of the arm 75 through a rotarysolenoid operated actuator 81 as more fully disclosed in the cited HughSt. Lawrence Dannatt U.S. Pat. No. 3,327,828.

The solenoid actuator 81 is normally maintained energized by theassociated equipment to which coded data infomration is supplied bymanual manipulation of the keyboard mechanism including the key shiftmechanism. The latch restore bail is thus normally maintained in itsrearmost position. i

The key shift mechanism includes a rocker ann lever connected betweenthe shift key lever 18 and the unshift key lever 18a at 101 and 102,respectively. The rocker arm 100 is pivotally mounted on the pivot pin104 which is rotatable in a bushing 106 fixed to the bracket 108. Thepivot pin 104 is fixed along the length of the rocker arm lever 100 suchthat the length A of one side of the rocker arm lever 100 is greaterthan the length B of the other side of the rocker ann lever 100. inother words, A B, to compensate for the spring forces in the key shiftmechanism generated by the comb spring plate 24.

The rocker arm lever 100 includes a set of upper and lower tabs 111 and112 which are coupled to the shift key lever 18 and another set of upperand lower tabs 113 and 114 which are coupled to the unshift key lever180. It has been found that by having the upper and lower tabs 111, 112,113, 114 coupled to their respective key levers 18, 18: a positivecarnming of the shift key lever 18 and unshift key lever can beachieved. It should be understood, however, that the rocker arm lever100 can achieve the same results by the use of the upper tabs 1 11 and113 only or slots on the ends of the rocker arm lever 100 to receive theshift key lever 18 and the unshift lever 18a. The rocker arm lever 100couples the shift key lever 18 to the unshift key lever 18a in phaseopposition or, in other words, the shift key lever 18 is out of phasewith the unshift key lever 180 as will be shown hereinafter. For thispurpose, a means such as a bail 116 and a spring 117 fastened to baseplate 12 urge the shift key lever 18 to a normally unlatched or restposition as shown by FIG. 1 while the unshift key lever 18a is disposedin the down position as shown by FIG. 1.

The key shifl mechanism also includes another shift key lever 18!; whichis of similar construction to the shift key lever 18 except that theslide mechanism 47 and pawl 39 together with the associated structure isomitted since shifi key lever 18b is coupled to shift key lever 18 andhail 116. The shift key lever 18b includes a button 3017 similar to thebutton 30 of the shift key lever 18. The shift key lever 18b ispivotally mounted on the rod 21 and is urgedto the up positionby thespring 117 in a manner similar to the shift key lever 18.

The sequence of operations of the shiftkey lever 18 and the unshift keylever 18a is more fullydescribed in the copending application of HughSt. Lawrence Dannatt entitled Key Shift Mechanism," Ser. No. 5 9,754,filed Nov. 1, 1967, and assigned to the same assignee as the presentapplication. The shift key lever 18 and the unshift key lever 18a arebasically the same and operate in the same manner. The shift key lever18 is shown as being disposed in a normally up position as shown in FIG.1, while at the same time the unshift key lever 18a is shown as beingnormally disposed in the down position of FIG. -1. The shift key lever18 and the unshift key lever18a operate in asimilar manner to provide acode representing upper case and lower case'characters, and figuresrespective- 1 FIG. 1 illustrates the normal latched position of slidemember 47 prior to manual pivotal actuation of the'shift button30 andthe shift key lever 18, the latter thus engaging the stop bar 23 and thelatch portion 58 of the slide member 47 being in full latchingengagement with its associated latch roller 59. The latch restore bail73 is held in its rearrnost position at this time by energization of thesolenoid actuator 81 as earlier described. At the same time theunshiftkey lever 18a is normally held in the positionas shown in FIG. 1.

The shift key lever 18 may be manually depressed sufficiently far thatthe associated pawl 39 engages and pivots the slide member 47 beneathits point of latched engagement with thea ssociated latch roller 59. Thenose of the latch portion 58 of the slide member 47 accordingly is movedbelow the axis of the roller wire 60, so the that latching engagementcan no longer be maintained by reason of the rearward force exerted byan associated finger of the comb spring plate 57 on the slide i member47. Since the slide member 47 is movable downward and longitudinally ina rearward direction, the nose of the latching portion 58 of the slide'member 47 continues to engage and rotate the latch roller 59 thus tominimize any frictional forces which may be associated with theunlatching operation and thereby reduce the downward force necessarily aexertedon the key lever 18 to effect unlatching of the slide member 47.It may be noted, as illustrated in FIG. 1, that the force exerted by theactuating projection 45 of the pawl 39 on i the end of the slide member47 maintains the pawl 39 substantially nonpivoted on the shift key lever18 not notwithstanding the bias force exerted by the spring 43 on thepawl 39. The interlock portion 62 of the slide member 47 may be movedbetween adjacent balls 63 of the interlock structure to prevent similar.unlatching of any other slide member including the slide member 47aassociated with unshift key lever 18a. The .unshift key lever 18a is outof phase with shift key lever 18 but follows the same sequence ofoperation as the shift'key lever The latch restore bail E restores anyunlatched slide membersuch as members For 47a to the latched position,the action of slide member 47 will be described and it will beunderstood that the action of slide member 470 could be identicallydescribed by substituting theletter a after the numbers designating theappropriate elements. As the slide vanes (not shown) are pivoted by thecoding teeth 69 against the bias. spring force of the code selectorcontacts (not shown). This bias force tends to pivot the slide member 47upwardly at its forward end; the upper edge surface of its latch portion58 accordingly tends to continue to maintain rolling I edeof 7 l member47 moves rearwardly to its rea'rmost position, coding It will berecalled that a solenoid actuator 81 is deenergiz ed by the associatedequipment as the latter initiated a cycle of operation and in responsethereto the restore bail 73 is pivotally displaced in a forwarddirection causing it to e hgage the downwardly projecting restoreportion 90 provided on the lower edge of the slide member 47 so thatcontinued forward motion of the restore bail rod 74 moves the slidemember 47 in a forward direction toward its relatchable position withthe associated latch roller 59. The slide restore portion 90 has asloping cam surface 91 which when engaged by the restore bail rod 74exerts a pivotal upward force on the forward end of the slide member 47to lift it into latchable engagement with the associated latch roller59. Here again the continued engagement of the upper flat surface of thelatch portion 58 with the latch roller 59 minimizes the frictionalforces involved in the slide restore operation. The forward end of theslide member 47 while moving in a forward direction engages the side ofthe pawl actuating projection 45 and forces the pawl 39 forwardly on theshift key lever 18 against the tension of the spring 43 so that theslide member 47 may move in a forward direction to a fully latchedposition without engagement of the pawl actuating projection 45 with theupper end surface of the slide member 47. As the latch restore bail Acontinues its forward movement, the restore bail rod .74 begins to rideunder the nose of the slide restore portion 90 and thus forcibly movesthe forward end of the slide member 47 upwardly toward latchingengagement of its latch portion 58 with the latch roller 59. Therestored bail rod 74 moves beneath the slide restore portion 90 justafter the nose of the latch portion 58 of the slide member 47 iselevated an incremental amount above the axis of the latch rollersupport wire 60. at which time the sloping edge surface of the latchrestore portion 58 lifts the slide member 47 upward to fully latchedposition on the latch roller 59 by reason of the rearwardly directedforce exerted by the comb spring plate 57 (FIG; 1) on the slide member47. This disengages the slide restore portion 90 and restore bail rod 74so that the restore bail 73 thereafter completes its forward motionwithout restraint by any of the latched slide members such as slidemember 47. In summary, it should by observed that after depressionofshift key button 30 and the consequent depression of shift key lever 18,the slide 47 went through a cycle of motion wherein it was first movedtoward the rear of the structure and then restored to the front and alatched position by the action of restore bail rod74. Thus, the slidemember 47 may complete its cycle of motion even though the shift keylever 18 is held in a downward position. Furthermore, in response to thedownward motion of the shift key lever 18 the unshift key lever 18a atthe same timeundergoes a complimentary displacement and is now in the upposition and is prepared tobe depressed by the rocker arm lever 100. inother wo'rds, the unshift key lever 18a is nowis in the same positionthatgthe shift key lever 18 was at thestart (FIG. 1).

With the shift key lever 18 held in a'fully depressed or down position,the slidemember 47.may be restored to afully latched position with itsinterlock portion 62,out of engagement with the interlock balls 63.While the restore bail rodf7 4 underlies therestore portion 90 of allslide memberssuc-h as 47 and 470 it thereby locks them against pivotalmotion unlatched position until the restore bail rod 74, hasiagain movedrearwardly sufi'iciently far as to no longer underli the restore portion90 of any slide members. such as 476; 471;. Thus deenergization of thesolenoid actuator 81, as by removal of power from the associated datautilizingeqpipment, causes the restore bailrod 74 to move to. its forsvalrdv most position. where it locks all slide members such as .47against motion in response to manual manipulation of their associatedkey levers (such asl8). The pawl 39 remains longitudinally displaced onthe key lever 18 with the pawl actuating projection 45 yet in sideabutting relation to the. end of the latched slide member 47 so that thelatter cannot again be .un latched by the pawl 39 until the key lever 18is once more restored to its normal uppermost or nonoperated position toreestablish the overlapping raation between the pawl actuatingprojection 45 and the end of the slide member 47 as illustrated inFIG. 1. Even though the shift key lever 18 remains so depressed for aprolonged interval, other key levers of the keyboard may be manuallydepressed to pivot and unlatch their respective associated slide memberssimilar to slide 47 as soon as the restore bail rod 74 has been movedrearwardly by reenergization of the solenoid actuator 81. The unshiftkey lever 18a follows the same operation as that shown for the shift keylever 18 but with an out of phase, or complementary, relationship.

From the operation of the shift key lever 18 and the unshift key lever18a, it may now be seen that the rocker arm lever 100 couples the shiftkey lever 18 and the unshift key lever 18a in phase opposition for uppercase and lower case characters, respectively.

In accordance with the invention, the key lock mechanism includes a keylock lever 18c which is substantially of the same structure as the keylevers 18, 18a, except that the key lock lever 18c includes a bridgingmember or tab portion 121 which coacts with the projection 35 of the keyshift lever 18 for depressing the shift key lever 18 as a unit. The keylock lever 18c is pivotally mounted on the rod 21 and is urged in aclockwise direction by the comb spring plate 24. There exists a firstadjustable space between the projection 35 and the tab portion 121. Thisfirst space is effectively a built-in time delay for the sequentialoperation of the key lock lever 18c and the shift key lever 18. That is,when the key lock lever 18c is operated, the tab portion 121 movesthrough the space before it coacts with the projection 35. The key lockmechanism also includes a locking member 122 which is pivotally mountedon the key lock lever 180 by a pivot pin 124. The locking rriember 122is retained laterally by a washer member 125 in a manner well-known tothose skilled in the art. The locking member 122 is yieldingly urged ina clockwise direction by a spring 126. The spring 126 is retained at end129 in an aperture 127 in the key lock lever 18c and is retained at theother end by an upturned portion 128 coacting with the locking member122. The locking member 122 includes a notch portion 130 which coactswith the bar 23 for retaining the key lock member 18c in a depressedposition which in turn retains the key shift member 18 in a depressedposition by the tab 121 acting on the vertical projection 35. The keylock mechanism also includes a bridging member 131 which is fixed to avertical projection 132 of the key shift lever 18 and includes a portion133 which coacts with the locking member 122 to retain or urge thelocking member 122 in a counterclockwise direction when the key shiftlever 18 is depressed. The tab 121 and the bridging member 131 bridgeother key levers, such as key lever 9 shown in fragmentary view. Thisgives added flexibility to the design of the keyboard. The portion 133of the bridging member 131 is positioned in cooperative relationshipwith the locking member 122 such that the locking member 122 engages thebar 23 when the key lock lever 18c moves at the end of its limit oftravel. Another or second space or second clearance exists between thelocking member 122 and the portion 133 of the bridging member 131. Thissecond space or second clearance is greater than the adjustable space orclearance between the tab 121 and projection 35 and provides a timedelay between the operation of the key lock lever 18c and the shift keylever 18. The depression of the shift key lever 18 releases the key lockmechanism. This second clearance or spacing allows the locking member122 to rotate clockwise to engage the stop bar 23 when the key locklever 18c is depressed. However, when the shift key lever 18 is operatedbefore the key lock lever 180; it closes the second space or secondclearance between portion 133 and member 122 and exerts acounterclockwise force on the locking member 122 to retain'it in asubstantially counterclockwise position to avoid engagement with the bar23 during its upward travel.

FIGS. 2 and 3 show the locking member 122 in a locked position and in anunlocked position, respectively. It should be noted that when thelocking member 122 is in the lock position, the portion 133 of thebridge member 131 is spaced from the locking member 122 by the secondclearance which is sufficient for the notch to engage the bar 23.Referring to FIG. 3, the locking member 122 includes a tab portion 137which coacts with the key shift lever 18 for depressing the key locklever when a force is exerted on the locking member 122 by the portion133 of the bridging member 131.

In the operation of the key lock mechanism, the shift key lever 18 maybe locked in a shift position by the depression of the lock button 134.When the lock button 134 is depressed, the tab portion 121 moves throughthe small clearance between the vertical projection 35 and the tabportion 121 to effect a short time delay during which the space betweenthe portion 133 and the locking member 122 increases. This may be seenby observing the position of the pin 124 on the key lock lever18 as itis depressed. Since this distance is increased and the locking member122 is biased in a clockwise direction, the notch 130 engages the stopbar 23 locking the key lock lever 18c and the shift key lever 18 in theshifted position. During this shift operation, the shift key lever 18and the unshifi key lever 18a together with their associated slidemembers 47, 47a operate in the manner set forth hereinbefore. When it isdesired to unlock the shift key lever 18, the shift key button 30 isdepressed so that the bridging member 131 and the portion 133 rotate thelocking member 122 in a counterclockwise direction to disengage thenotch 130 from the stop bar 23. The comb spring plate 24 continuouslyurges the key lock lever 180 in an upward direction. Thus, the pivot pin124 is also moved in an upward direction to decrease the gap or spacebetween the portion 133 and the locking member 122 to a point at whichit contacts the portion 133. This in turn urges the locking member 122in a counterclockwise direction to keep the notch 130 away from the stopbar 23 and thus permits the shift key lever 18 to return to theunshifted position as previously described.

From the foregoing description, it may be seen that the key lockmechanism provides for the positioning of additional key levers betweenthe key lock lever 18c and the shift key lever 18. Thus, greater varietyin the arrangement of the keyboard can be achieved by the utilization ofthe present invention.

While there has been described a specific form of the invention forpurposes of illustration, it is contemplated that numerous changes maybe made without departing from the spirit of the invention.

I claim:

1. A key lock mechanism for a keyboard having a plurality of key leversincluding a shift key lever which is movable between a normallyunshifted position and a shifted position. said key lock mechanismcomprising:

a. a key lock lever mounted in spaced relationship to said shift keylever for movement between corresponding normally unshifted and shiftedpositions;

b. a fixed bar;

c. locking means including a spring biased locking member pivotallymounted on said key lock lever for latching said key lock lever in saidcorresponding shifted position when moved thereto;

d. a first bridging means mounted on said key lock lever and coupled tosaid shift key lever for urging said shift key lever to said shiftedposition; and

e. second bridging means mounted on said shift key lever and coupled tosaid locking member for decoupling said locking member from said fixedbar when said shift key lever is shifted before said key lock lever.

2. The invention defined in claim 1 wherein said key lock lever isspaced from said shift key lever by at least one key lever.

3. The invention defined in claim 1 wherein said key lock lever isspaced from said shift key lever by at least one key lever and saidfirst and second bridging means span said one key lever.

4. The invention defined in claim 1 further including a lock button onsaid key lock lever for operating said key lock lever.

and said shift ke of said tab portio y lever being responsive to thedisplacement n.

6. The invention defined in claim member is pivotally disposed on a pivlock lever 1 wherein said locking ot pin fixed to said key

1. A key lock mechanism for a keyboard having a plurality of key leversincluding a shift key lever which is movable between a normallyunshifted position and a shifted position, said key lock mechanismcomprising: a. a key lock lever mounted in spaced relationship to saidshift key lever for movement between corresponding normally unshiftedand shifted positions; b. a fixed bar; c. locking means including aspring biased locking member pivotally mounted on said key lock leverfor latching said key lock lever in said corresponding shifted positionwhen moved thereto; d. a first bridging means mounted on said key locklever and coupled to said shift key lever for urging said shift keylever to said shifted position; and e. second bridging means mounted onsaid shift key lever and coupled to said locking member for decouplingsaid locking member from said fixed bar when said shift key lever isshifted before said key lock lever.
 2. The invention defined in claim 1wherein said key lock lever is spaced from said shift key lever by atleast one key lever.
 3. The invention defined in claim 1 wherein saidkey lock lever is spaced from said shift key lever by at least one keylever and said first and second bridging means span said one key lever.4. The invention defined in claim 1 further including a lock button onsaid key lock lever for operating said key lock lever.
 5. The inventiondefined in claim 1 wherein said first bridging means includes asubstantially horizontal tab portion and said shift key lever beingresponsive to the displacement of said tab portion.
 6. The inventiondefined In claim 1 wherein said locking member is pivotally disposed ona pivot pin fixed to said key lock lever.